basic stats 3

1.The # of tow calls coming into an tow truck station on Tuesday (between 7:00 - 8:00 AM) has a probability dist. With a mean of four.i) State what type of prob. Dist. would be appropriate for this. ii) Find the prob. of not getting any emergency tow calls between 7-8 a.m.iii) Find the prob. of receiving 5 emergency tow calls between 7-8 a.m.iv) List what is the # of emergency tow calls expected to be received.v) List what is the std. dev. of emergency tow calls received.

Just a bunch of questions. At this level of stats - theres only one distribution that has as its parameter the mean of a population. Knowing which distribution that is should help you do the rest of the problems.

So is this Poisson then?
Next queston is:
I was gone for an entire week and missed how to do these problems.
I have a TI-89 calculator (titanium model). How do you set up the first problem?
Example:
For the first one I coem up with u=4;P(x<=0)= ... but not sure how to enter this in my calc.